Screening methods for identifying agents that modulate output of a circadian pacemaker

Abstract

The invention provides a method for screening for a compound for modulating circadian rhythm. The method involves (a) providing a compound that is a Prokineticin 2 (PK2) receptor antagonist or agonist; and (b) determining the ability of the compound to modulate one or more indicia of circadian rhythm function, wherein a compound that modulates one or more indicia of circadian rhythm function is identified as a compound for modulating circadian rhythm. The invention also provides a mouse PK2 receptor nucleic acid, polypeptide and related compositions. Further provided is a method for modulating circadian rhythm of an animal, which involves administering an effective amount of a PK2 receptor antagonist or agonist to an animal. Also provided is an isolated nucleic acid comprising a PK2 gene promoter operatively linked to a heterologous nucleotide sequence.

What is claimed is: 
     
       1. A method for identifying an agent that modulates output of a circadian pacemaker of a suprachiasmatic nucleus (SCN), comprising:
 (a) contacting a sample comprising a prokineticin 2 (PK2) receptor as set forth in SEQ ID NO:2 with at least one test agent, under conditions suitable for the PK2 receptor to bind to the test agent; and 
 (b) detecting circadian locomotor activity induced by the test agent as compared to the circadian locomotor activity induced by a known PK2 receptor modulating agent, wherein the known PK2 receptor modulating agent is human PK2, 
 thereby identifying the test agent as an agent for modulating output of the circadian pacemaker of the suprachiasmatic nucleus (SCN). 
 
     
     
       2. The method of  claim 1 , wherein the test agent is administered to an animal having an observable circadian locomotor activity associated with the output of the SCN. 
     
     
       3. The method of  claim 2 , wherein the animal is a mammal. 
     
     
       4. The method of  claim 3 , wherein the animal is selected from human, non-human primate, rat and mouse. 
     
     
       5. The method of  claim 2 , wherein the activity is wheel-running activity. 
     
     
       6. The method of  claim 1 , further comprising contacting the PK2 receptor under conditions wherein the test agent promotes a signal as compared to the known PK2 modulating agent. 
     
     
       7. The method of  claim 6 , wherein the signal is calcium ion mobilization. 
     
     
       8. The method of  claim 6 , wherein the receptor is contacted with greater than about 100 candidate test agents. 
     
     
       9. The method of  claim 6 , wherein the receptor is contacted with greater than about 10 5  test agents. 
     
     
       10. The method of  claim 6 , wherein the receptor is contained in a human cell preparation. 
     
     
       11. The method of  claim 1 , further comprising contacting the PK2 receptor under conditions wherein the binding of the test agent to the PK2 receptor is compared to the binding of the known PK2 receptor modulating agent, wherein similar binding to the PK2 receptor of the test agent and the known agent identifies the test agent as an agent that binds to and activates the PK2 receptor. 
     
     
       12. The method of  claim 10  or  11 , wherein the PK2 receptor is contacted with greater than about 100 candidate test agents. 
     
     
       13. The method of  claim 10  or  11 , wherein the receptor is contacted with greater than about 10 5  test agents. 
     
     
       14. The method of  claim 11 , wherein the receptor is contained in a human cell preparation.